This is my first time travelling to London and I'm very confused by the travel infrastructure here. When I landed at Heathrow, I bought a 7 day Oyster card for Zone 1-2 and I was charged £43 for it. After I took my journey to Central London and I saw the balance, it said that it had deduced £1.5 and my remaining balance was just £3.5.
Where did the rest of my £38 go?
The terminology does get confusing. Basically, you have an Oyster card with:
A "7-day Zone 1 & 2 Travelcard" on it. This gives you free travel within Zones 1 & 2 for 7 days. It is worth £33 and it will...
...let you travel as often as you like on bus, Tube, tram, DLR, London Overground and National Rail services within the London travel zones [in this case, zones 1 and 2].
£5 credit which is used when you travel outside of zones 1 and 2, or if you're still using it after the 7 days are up.
So, when you travelled from Heathrow (which is in Zone 6), you paid from the card's credit for the stretch of the journey to Zone 2. Now you're in central London, you get free tube and bus travel within Zone 1 & 2.
